We propose to investigate the hypothesis the lens is a syncytial tissue, composed of many fiber like cells surrounded by intact plasma membranes, but all electrically coupled through gap junctions. The normal electrical properties of the lens fibers, gap junctions and lens epithelia will be determined using microelectrodes to measure the impedance of the lens to sinusoidal currents and comparing these data with theoretical expressions derived from the morphometry of the lens. The electrical properties of experimentally altered lenses will also be determined through impedance analysis techniques. The experimental interventions include altering the extracellular cation composition and transport rate of the anterior epithelium in order to quantitatively understand the mechanism of volume regulation in a syncytial tissue such as the lens. Another intervention will be to introduce in vitro lenses to high concentrations of cataractogenic steroids and measure the effect on the electrical properties and transport in these lenses. In vivo experiments are planned where cataracts will be induced and the change in normal electrical and transport parameters will be measured. The major goal in each of the proposed experimeets is to quantitatively separate the properties of inner fiber membranes, gap junctions, and surface/epithelial cell membranes using impedance analyses then, by using metabolic inhibitors to assess the transport rate in these lenses, we hope to understand the response of the lens to the experimental intervention we have imposed.